In recent years, there has been worldwide diffusion of a system for transmitting and receiving an e-mail via a network such as the Internet or an LAN (Local Area Network). A PC, a cell-phone and the like are heavily used as devices for transmitting and receiving the e-mail. This system normally has a mail server intervening between a transmission side device and a reception side device of an e-mail. The e-mail transmitted from the transmission side device is once stored in a mail server and is then transmitted to the reception side device from the mail server.
Normally, each individual device has a mail address unique to it, and the mail address is managed by the mail server of the system to which the device subscribes. A user of each individual device sometimes needs to change the mail address of the user's own device from a viewpoint of a measure for junk mail rejection for instance. This mail system is configured to allow the mail address of the device to be changed.
Here, as for the user who has changed the mail address of the user's own device, it is conventionally necessary to notify the devices of persons concerned including friends and business partners who are likely to transmit an e-mail to the user's own device of the change of the mail address and a new mail address thereof after the change so as to have the persons concerned recognize the change of the mail address. This work normally requires considerable labor. And those who have received the notification need to accurately register the new mail address with an address book or accurately update the address book each time new mail addresses are notified by various parties. This management of the mail address is considerably burdensome.
To alleviate this burden, Patent Documents 1 and 2 make a proposal that, upon receiving the notification of change of the mail address, the address book of the reception side device is automatically updated with a new mail address after the change. Patent Document 3 makes a proposal to intensively manage a telephone directory with a database and notify each personal telephone from a database device upon a change of a telephone number so that each personal telephone automatically updates the telephone directory stored therein with the telephone number notified of.
Patent Document 1: Japanese Patent Laid-Open No. 6-139164
Patent Document 2: Japanese Patent Laid-Open No. 2001-356984
Patent Document 3: Japanese Patent Laid-Open No. 2000-196771